The van der Waals epitaxy of Bi₂Se₃on the vicinal Si(111) surface: an approach for preparing high-quality thin films of a topological insulator

Abstract

Epitaxial growth of topological insulator Bi2Se3 thin films on nominally flat\nand vicinal Si(111) substrates is studied. In order to achieve planner growth\nfront and better quality epifilms, a two-step growth method is adopted for the\nvan der Waal epitaxy of Bi2Se3 to proceed. By employing vicinal Si(111)\nsubstrate surfaces, the in-pane growth rate anisotropy of Bi2Se3 is explored to\nachieve single crystalline Bi2Se3 epifilms, in which threading defects and\ntwins are effectively suppressed. Optimization of the growth parameters has\nresulted in vicinal Bi2Se3 films showing a carrier mobility of ~ 2000 cm2V-1s-1\nand the background doping of ~ 3 x 1018 cm-3 of the as-grown layers. Such\nsamples not only show relatively high magnetoresistance but also a linear\ndependence on magnetic field.\n